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Volume 76, Issue 1
Displaying 1-9 of 9 articles from this issue
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Takayuki MIYAKE, Jun UETAKE, Sumito MATOBA, Akiko SAKAI, Koji FUJITA, ...2014 Volume 76 Issue 1 Pages 3-17
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSIn order to reconstruct the past climate and environmental changes, we carried out sampling and chemical analyses of surface snow and ice, and precipitation on Qiyi Glacier, Qilian Mountains, western China, in August and September 2004. A mean pH value of surface snow and ice was 7.07. We found high correlation (r=0.98) between difference of total cations concentration and total anions concentration (ΔC) and Ca2++Mg2+ concentrations. It was indicated that these sources were carbonate mineral such as CaCO3 in soil and loess and these species influenced pH of surface snow and ice of the glacier. The chemical composition of Qiyi Glacier was similar to that of glaciers of the Tien Shan, suggesting that that of the glacier was strongly affected from aeolian dust from arid/semi-arid regions. It was suggested that a source of Na+ and Cl− in surface snow and ice was mainly rock salt (halite) at the glacier, because both species had high correlation (r=0.93) and mean of Na+/Cl− ratio was almost 1.00. Ratios of Ca2+，Mg2+ and ΔC to total ionic concentrations were predominant in surface snow and ice and precipitation and greater in ice and snow than in precipitation at the glacier. It was suggested that these were influenced by dissolution of dust with melt-freeze processes and dry deposition. The sources of chemical species except NH4+ in the samples were estimated such as soil and dust, anthropogenic and rock salt based on the results of the principal component analysis (PCA).View full abstractDownload PDF (2212K) -
Takanobu SAWAGAKI, Satoru YAMAGUCHI, Yousuke ABE2014 Volume 76 Issue 1 Pages 19-31
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSGlacial equilibrium line altitude (ELA) is an important indicator of regional climate conditions. Especially for the paleo-ELA, a number of previous studies have estimated it using Accumulation Area Ratio (AAR) implemented in the two dimensional glacial extents reconstructed by the various glacial geomorphological techniques. However, there is few verification from the viewpoint whether the reconstructed glaciers are appropriate dynamically or in mass balance. Thus, this study attempts to develop a three dimensional ELA estimation model. This model calculates mass balance at given cross sections of a glacier determined by bed and glacial surface morphology. The position of the section where positive/negative mass balance interchanges is regarded as its ELA. We verified this model using the currently existing glaciers in Switzerland and Sweden. As a result, the calculated ELA showed the same altitude as observed ones. In some case, ELA was detected by two or more altitudes of the glacier that has ice thickness changes along the flow line due to the bed topographic variation. These results show that the shape of glacier surface or bed topography serves as important parameters which influences reconstruction of paleo-ELA.View full abstractDownload PDF (1796K) -
Takanobu SAWAGAKI, Satoru YAMAGUCHI, Yousuke ABE2014 Volume 76 Issue 1 Pages 33-43
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSAn ELA determination model (GS model) developed in the integration of glacial flow model and glacial geomorphology was applied to some reconstructed late Pleistocene glaciers in the northern Hidaka range. As a result, differences in paleo-ELA were appeared between the models with and without consideration of the glacial surface topography. Also, paleo-ELAs were highly multiple in the glaciers those ice thickness are largely changed along the flow line due to the undulation of the bed topography. These results show that bed and ice surface topographies are important parameters which influences the restoration of the paleo-ELA. Readjusting parameters in trial and error according to the result of model calculations strongly suggests the possibility of more accurate three dimensional reconstruction of the past glaciers.View full abstractDownload PDF (2377K) -
Koji MATSUO, Kosuke HEKI2014 Volume 76 Issue 1 Pages 45-57
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSThe advent of space geodetic satellites as represented by the gravimetry satellite GRACE and the laser altimetry satellite ICESat has enabled remote and continuous monitoring of the glacier mass balance in extensive areas of Asia high mountains. As of now, the glacier mass balance there has been estimated by Matsuo and Heki (2010) and Jacob et al. (2012) using GRACE gravity data. However, these two estimates are significantly different each other, i.e. the former suggests substantial ice loss of〜47 Gtyr−1, and the latter does slight ice loss of〜11 Gt yr−1. In this article, we review these two studies and describe several important points to consider when studying Asian high mountains with GRACE. Then we re-estimate the glacier mass balance there using the latest GRACE data set (Release05) and the new inversion technique. We also review the latest reports based on the ICESat laser altimetry.View full abstractDownload PDF (3379K) -
Takahiro SEGAWA, Ka zunari USHIDA, Shiro KOHSHIMA2014 Volume 76 Issue 1 Pages 59-67
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSGlacier microorganisms are an ideal target for studies of the functionalities, structures, and environmental responses in ecosystems due to the simpler structure of the glacier ecosystem. Phylogenetic analyses of bacteria revealed the presence of the particular bacteria growing in the glacier environment and adapting to the particular micro-environment. Bacterial communities in the glaciers were divided into three types based on their habitat: snow-covered or snow- and ice- covered or bare-ice areas. In addition, the bacteria trapped in ice cores are now regarded as novel environmental markers for the past environment. Bacteriological analyses of ice cores have the potential to reconstitute the past environment. Since many intestinal bacteria were detected in the snow samples, we have conducted studies about antibiotic-resistant genes in the glacier environment. This is because animal intestines are the best places for selection and propagation of antibiotic-resistant bacteria. The detection of antibiotic-resistant bacteria in glaciers, which are very far from human industrial activity, implies human impact on nature. Here, we show the prevalence of antibiotic-resistant genes in 54 snow and ice samples collected from the Arctic, Antarctic, Central Asia, North and South America, and Africa, to evaluate the level of human impact on the environment. Antibiotic-resistant genes are widely distributed in Central Asia, North and South America, Greenland, and Africa. In contrast, Antarctic glaciers (>70° S) were virtually free of these genes. Our results suggest the major origin (northern hemisphere) and transmission (atmospheric circulation) of these genes.View full abstractDownload PDF (1410K) -
Koji FUJITA2014 Volume 76 Issue 1 Pages 69-78
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSIn 2009, a report has highlighted inadequacies in a 2007 report by the Intergovernmental Panel on Climate Change, and then the present status of Himalayan glaciers and their fate are a matter of great concern. Various studies have been published during the succeeding years, as a consequence of “the Himalayan Glaciergate”. In this review article, I describe how the inadequate descriptions have been embedded in the IPCC report and how the IPCC had corrected the inadequacies. I also present an overview of relevant studies dealing with Himalayan and/or Asian glaciers in terms of in-situ observation, modeling, and remote-sensing approaches.View full abstractDownload PDF (1713K) -
Akiko SAKAI2014 Volume 76 Issue 1 Pages 79-89
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSThe ablation model for debris-covered glaciers that uses thermal resistance, which includes both debris thickness and thermal conductivity of the debris layer and requires only surface temperature and meteorological data to be acquired simultaneously. However, this method overestimates the ablation amounts for thick debris layers, since it neglects changes in heat storage in the debris layer. Conversely, recent studies on debris-covered glaciers have concentrated on developing the physical model of ablation of debris covered ice. However, physical model requires several parameters such as thermal conductivity and thickness of debris layers, which are difficult to obtain without digging debris layers. Therefore, it is difficult to employ this model over a wide area. By considering the advantages and disadvantages of each physical model, we could improve the ablation model of debris-covered glaciers.View full abstractDownload PDF (1795K) -
Nozomu TAKEUCHI2014 Volume 76 Issue 1 Pages 91-103
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSGlaciers are inhabited by various organisms, which are adapted to cold environments of snow and ice. Studies have recently revealed existence of such organisms on glaciers worldwide and distinctive characteristics of their community on Asian glaciers. Snow and ice algal communities on Asian glaciers are characterized by abundant cyanobacteria. Cyanobacteria can form cryoconite granules, which are spherical aggregates of microbes, organic matter and mineral particles, on the ablation ice surface. The granules can reduces surface albedo and accelerate melting of glacier, thus, mass balance of Asian glaciers is substantially affected by the algae. The community also varies within Asia from Himalayas in south to Altai in north, probably due to gradients of climate and vegetation from the south to the north of Asian high mountains. Bacterial communities on Asian glaciers have recently been revealed by DNA analysis and also varied with geographical and climate conditions. Ice cores drilled on themountain glaciers enabled us to study temporal variations in the microbial communities for decades to centuries. Studies on microbial communities on Asian glaciers is important to evaluate effect of recent global warming on cryosphere and glacial ecosystemsView full abstractDownload PDF (3753K) -
Takayuki NUIMURA2014 Volume 76 Issue 1 Pages 105-114
Published: 2014
Released on J-STAGE: March 01, 2023
JOURNAL OPEN ACCESSDownload PDF (1125K)
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